Synthesis of Size-Selected Ag Nanoparticles for Studies of Electron-Phonon Coupling in Finite-sized Systems.

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A nanoparticle is a collection of thousands of atoms in a typically spherical shape with a diameter of 1 to 100 nm.These particles are bits of matter that lie somewhere between the atom and the bulk.Their chemical and physical properties are of considerable importance in understanding finite-sized systems.One such physical property is electron-phonon coupling. In bulk metal, the energy of excited electrons will be dissipated by the phonons or lattice modes.In a small particle, the lattice modes are quite different than in the bulk and may not be as effective in quenching the electrons.Therefore, in a finite-sized particle, it is suggested that the excited electrons will escape the metal.Low intensity light of the second harmonic of a Nd:YAG laser (532 nm) will be directed at a two-dimensional array of the Ag nanoparticles to excite electrons and the intensity of the ejected electrons will be measured.To realize this experiment, silver nanoparticles passivated with dodecanethiol have been synthesized, size-selected, and characterized by Ultraviolet-Visible Absorption and Transmission Electron Microscopy.A two-dimensional crystalline array of Ag nanoparticles has been formed on Langmuir Trough. Electron Microscopy and Atomic Force Microscopy will be used to characterize the arrays. Finally, the supported array will be mounted in a high vacuum chamber for laser interrogation.


E. M. Spain




Camille & Henry Dreyfus Foundation

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